There is a specification for firing pin protrusion on the AR-15. Brownells sell a Firing pin Protrusion gauge. Minimum protrusion is .028 and maximum is .036 or .008 tolerance.
Ive researched firing pin lengths and the most consistent info indicates a maximum firing pin length of 3.279 with a minus -.009 tolerance. I have one Colt Firing pin which measures 3.2800. The problem which has come up with the 6.5 Grendel is the bolt overall length. Alexander Arms chose to use a .136 bolt face depth. A 5.56/223 bolt uses a .125 bolt face depth +or- a tolerance of .001-.002. The 5.56/223 bolt overall length is 2.800 +or- minus tolerance (measured from the tail to the face of the lugs).
Alexander Arms lengthened the 6.5 Grendel bolt to 2.810 to account for the deeper bolt face depth and permit the usage of mil spec firing pins. Without measuring the bolt and firing pins or using a FP protrusion gauge there is no way of knowing if your FP protrusion is in spec.
There have been a couple instances where forum members experienced erratic failure to fire which were traced to inadequate firing pin protrusion. Excessive firing pin protrusion is more common and results are pierced primers and a greater chance of a slam fire. A few manufacturers have supplied 2.800 length 6.5 Grendel bolts with a .136 bolt face depth. Not all these bolts were supplied with shorter firing pins to get the FP protrusion in spec. If your using a 2.800 length bolt your firing pin needs to be 3.269 or shorter or there is a chance youll have excessive FP protrusion.
I remember when Hornady switched from the nickel colored primers to brass color primers and pierced primers were more common with the brass primers. As far as I know Hornady never acknowledged a problem with the brass primers. I always assumed the brass primers were softer or had thinner cups. After being on the forum and reading about the issues over the years with the variations in firing pin lengths and the actual measured length of the bolts. I wondered if part of the brass colored primer problems were because of tolerance stacking or firing pin protrusion being out of spec or on the longer side.
Well probably never know but after experiencing pierced primers on 223 Remington reloads using standard Remington small rifle primers in an AR-15 I decided to switch to CCI 450 or CCI 41 primers. Ill use my standard small rifle primers in my bolt action.
Ive researched firing pin lengths and the most consistent info indicates a maximum firing pin length of 3.279 with a minus -.009 tolerance. I have one Colt Firing pin which measures 3.2800. The problem which has come up with the 6.5 Grendel is the bolt overall length. Alexander Arms chose to use a .136 bolt face depth. A 5.56/223 bolt uses a .125 bolt face depth +or- a tolerance of .001-.002. The 5.56/223 bolt overall length is 2.800 +or- minus tolerance (measured from the tail to the face of the lugs).
Alexander Arms lengthened the 6.5 Grendel bolt to 2.810 to account for the deeper bolt face depth and permit the usage of mil spec firing pins. Without measuring the bolt and firing pins or using a FP protrusion gauge there is no way of knowing if your FP protrusion is in spec.
There have been a couple instances where forum members experienced erratic failure to fire which were traced to inadequate firing pin protrusion. Excessive firing pin protrusion is more common and results are pierced primers and a greater chance of a slam fire. A few manufacturers have supplied 2.800 length 6.5 Grendel bolts with a .136 bolt face depth. Not all these bolts were supplied with shorter firing pins to get the FP protrusion in spec. If your using a 2.800 length bolt your firing pin needs to be 3.269 or shorter or there is a chance youll have excessive FP protrusion.
I remember when Hornady switched from the nickel colored primers to brass color primers and pierced primers were more common with the brass primers. As far as I know Hornady never acknowledged a problem with the brass primers. I always assumed the brass primers were softer or had thinner cups. After being on the forum and reading about the issues over the years with the variations in firing pin lengths and the actual measured length of the bolts. I wondered if part of the brass colored primer problems were because of tolerance stacking or firing pin protrusion being out of spec or on the longer side.
Well probably never know but after experiencing pierced primers on 223 Remington reloads using standard Remington small rifle primers in an AR-15 I decided to switch to CCI 450 or CCI 41 primers. Ill use my standard small rifle primers in my bolt action.